I'm in need of some tube advice. I'm going to be changing the tubes of my Laney GH50L in a few months and I was just wondering what brands to look into. The tonal direction I'm going for would be something like Guthrie Govan's tone. I don't want to copy his tone (and obviously I can't) but I'd like to head in that direction. If that makes sense...

Oh and, I'm talking about power amp tubes, not preamp. Though suggestions still welcome.

Sorry to say a tube change wont change tone that much. Even going from something like 6L6 to EL34 the tonal change isn't much. The charactaristics may change a little. For example 6l6's generally have a bigger but looser bottom end compared to EL34's which have a more balanced tone.

Personally I don't like the tone of JJ tubes, they sound muddy and sterile to me. I think it's because of the tubes being "overbuilt" generally JJ's are durable because of this.
Chinese Shuguang- These are cheap tubes. I use these for powertubes because they are cheap, and are actually decent tubes. I prefer them over new Svetlanas. The 12AX7's tend to make good "high gain" tubes, they are bright sounding but sometimes can sound "fizzy"
Tung Sol's are good all around tubes. Low fail rate, good tone. I've found the 12AX7's to be "glassier" sounding with less mids than Mullards.
Mullards are nice and balanced sounding but they are priced a bit high and there's seems to be a fairly high fail rate with new tubes.

NOS tubes are fantastic, but often overpriced. Also i'd never buy NOS powertubes, unless I get a silly deal on them. Powertubes just need replacing too often to spend that much money on them. Pre-amp tubes can last decades so it can sometimes be worth the extra money.